Noncorrosive cooling agent



i Patented July 28,; 1925.

- 1 UNQITEDTISTATES- PATENT OFFICE.

GEORG' nnmmn'r, or memos, Gnnmm, ssIeNo-n 'ro nnmnAnrnn-wnnx i cnmusonn IABRIK ens. M. B; 11., or MUNICH, GERMANY.

nonconnosrvn- COOLING AGENT.

NoDrawing. i

To all whom it may concern:

Be it known that I, GEORG REINHART, a citizen ofthe German Republic, residing at Munich, Germany, have invented certain new and useful Improvements in Noncor- "rosive Coolin Agents, ofwhich the following is a speci cation.

The present invention relates to i mprove- --ments. in the provision and use of liquid .01 cooling and iefri'ge'rating agents of low .freezingpoint, with the object of forestalling freezing? thereof and particularly of preventing corrosion thereby of the metallic structural elements used-in the construc tion of the -.refrigerator or'other container.

The main drawback attaching to the use of thewell known liquid cooling media or freezing mixtures is thatthey all moreor less are. apt to corrodingly attack the metal container material, and bring this about it suflices that 'a metal, a metal alloy, or a soldering agent is used in the construction of the refrigerator structure the normal potential of which is more negative than that of the calcium, (Ca or magnesium '(Mg) of the best known -'re frigerant.

- Thus, for instance, barium, Whose normal potentialequalsminusfi, 1 presents a more negative normal potential than cadmium with its normal and, further, barium has a more negative normal -To a structuralelement of barium metal then there never would be imparted a deposit of magnesium or calcium, since. the

metal'elementitself would be dissolved for result] that the barium would be corroded.

the reason that. the dissolving tension of this more negative metal 1 is; greater than that of the Mg or Ca'respectively, with the refrigerator P8 11 This corrosive action is effectively obvi- 'ated if the'cooling solution iscompose'd of imetal" saltsw-hich on the one"hand differ toso e extent-from one another in normal potential, and on-th'e-other hand show. a

l more pronounced negative normal potential than the metal usedin thecon'struction of the refrigerator-.or othercontainer, or if there are several metals or alloys, 'than the.

- most negati-ve of such 'metals used. In this I instance, ifat anypoint'in the refrigerator even onl atrace of the solution metal is {there -W1l1: be a deposit on the g deposite Application nlea'ira 9,1922. Serial $10,5 9,412.

otential ofminus 2, 8;

potential than magnesium of minus rially,

most negative metal, the point of ,deposit serving as anode. It is these deposits, and not the refrigerator metals,"between which the local action, that is the electrical dissolving process, is initiatedand carried on.

,efi'ectively prevented.

By way of example: The practical experiments with light metals, for instance magnesium and calcium have already progressed so far that magnesium alloyscan A corrosion of the refrigeratormetalis thus now successfully be used in the manufacture of refrigerators. .To guard against corro= sion of the Mg alloy structural parts 1 pro poseto employ in place of the magnesiumcalcium chloride solution '(MgCl caCl' a CaCl; solution to which has been added a small amount of potassium chloride (KCl). The concentration of this solution is dependent upon the lowest operative temperature.

Zinc'will be'found in the Sada of every modern metal refrigerator, for which reason for practical purposes only such metal salts enter into the present solution the metals of which show a more negative normal poofmagnesium (1.83), of calcium (-2.8),

of potassium (3.2). Expressly excluded are. the salts which contain, beside 'one of tential than zinc, as for instance the salts rof sodium 2.99), of barium (-3.1) and the stated metals, 2. further metal of more positive normal potential; thus for instance chromium with a normal .pot entialof 0.8,

anda-s such for our purposes too high.

If a hromic compound sodium were used, the electrolyte would of potassiunilo'r chromic compoundsof potassium or sodiumcontain a metal ion whose normal potential- V of the zinc used in the refrigerator niate= rial, with the result that the latter would Y agenti. of, low

freezing point, consisting of an aqueous solution of magnesium chloride 7 and calcium chloride.

"ismore positive than the normal potential 2."Non-corros1ve cooling agent of *low freezing point, consisting of an aqueous xlution of substantially 80% magnesiuln amount, and zirelatively small i)eroentage Of. :chloride and substantially 20% calcium 1 potassium chloride. n

' approximately 25 B.

'freezing-point, consistin of an aqueous so- Witnesses:

chloride, the solution having a density of In testimony whereof .I aflix my signature V v y .in presence of two witnesses.

3. Non-corrosive cooling agent of low lution of magnesium c oride and dalpium ALBERT HALBTENER,

chloride, the former in predominant ALEXANDER DnSO'm.

GEORG R -INHARTQ 

